Telephone-exchange system.



F. LUBBERGER. t

TELEPHONE EXCHANGE SYSEN, APPLICATION mw 050191909, RENEwcD )uw an, 19m

1,295,181. mmm m., 2:, um

EENEWED JULY 1B. 1918.

Patented Feb. 25, 1919.

5 SHEETS-SHEET 2.

.4 hk-W W F.1UBBERGER. TELEPHONE EXCHANGE SYSTEM.

AwucAloN msn usc. lo. m09.

1r. u QQQmMQm- Q 1..... ..1 WQ bmw ....1 1- kmmfmm- 11 @im Qu? Mui. NvNvN \.,Q\1\11 NWB 1.

WWA/55555 P. LUBEERGER.

MLLHFHVQ *EXCHANGE SYSTEM. wmcsmow man DE: u 1M www um la1 1918.

14,295,181 Patented Feb. 25, 191%),

` 5 SHEETS-"SHEET 3 mmm/Tof?.-

F. LUBBEHGER.

TElEPHONE XCHANGE SYSTEM.

APPLlcAnoN man 050.10. |909. RENE-wsu JULY la, veis.

Patented Feb. 25, 1919.

5 SHEETS-SHEET 4.

, SLM .AZF

ATTORNEYS UNITED STATES PATENT OFFICE.

FRITZ LUBBERGER, 0F CHICAG, ILLINOS, ASSIGNR T0 AUTMATIC ELECTRIC COMPANY, 0F CHCGQ, ILLINGIS. A CORPORATION 0F ILLINOIS.

TELEPHONE-EXCHANGE SYSTEM.

Application led December 10, 1909, Serial No. 532.430.

To fr!! wlw/u J muy noncwrn:

Bo it known that I. Furrz Inuuiuuoicu. a suhjort ol the lirn'ioror ol' Germany and rosiilont o' Chit-ago1 @ook rounty` lllinoh.T havo in ventetl a certain new and uwfui lulproteuwut in Telephon@Exchange Statt-ms, ot' whit-h the 'following` is a Speeifiration.

My invention relates to telophonta oxuhangisyntouis in gonoral, so far as tho luoaler purpose@` of my inYention are' rour'ornell. hut more ,Spnffially to a\atiein:- of that hind in whit-h tho suhiseriheru lions tirzuiuate at llacentral Station` whieh am von nectetl ln' trunk lines with the main or renllal station.

Tho principal object of nl v invontiou ih, therefore, tho provision of noe-ana` whereby Ai subscrihor of ono suhcentral station ma)V all anothvr auhscriher of tlnl Haino station without calling: through the main or (central ata tion. rl'huh` a sulisvriber of ono .nihnoutral Station callsY a subscriber of another :no rentral utation hv extendingthe call through the main or central Station; hut a Sulcriher of ont: snlnfentral station oonnnuniiater; with another snlisrriher of the zaino station without oxtrnilingf tho call through the main or central station. Prior to my invention it was usual. in a listriet system. 'tot' all #solo to pass throng-h the main or nenti-al station. meu though tho calling` and L'alleil Subscribers were in tho ySaule group. Now, however. with my improved arrangement. calling anni tailed suhstrrihors of the @anto group communicate without the immunity of oxtoniling tho Call through the. main or new tral station. As I Say, though. ihtlfl H Itf roi-tain tentures of norelt)v whieh aro not. limited to a district system. and which may he used in various system.

The nature of my inrertion will hereinafter more fully appear.

In tho aco:unpanyingr drawings Figures 1. 2 and 3 taken together show the. completo circuit connections beween a fallingr substr tion A (Fig. 1l and '1S eallerl substation A2 (Fig. in a Systemunhoclying the prinoipies 0f my invention, there l'ieingr a vonnettor Switch Il by niveaus of whivh tho inh- Station ma;v obtain connection with tho substation of it.;l own exchange.

The apparatus shown in Fig. l azul tho Secondary switch C' and 11i-lister swith D' shown in Fig. :2 belong to a hraneh exchange. while the remaining apparatus. Shown in Specification of Letters Patent.

Renewed July 18, 1918. Serial No. 245,588,

Fig. belongs to a distant or niain o rhaulgge. Fig. 3 nallows a portion ot' the` apparatos 0I a second hranch excl'iange. To tho iino of suhstation A. there is allotted, at, the branch ernfhangl: the individual line ,switeh C, Thin.` line switch C, together with a ninnhor ot other similar switches. is controlled hy a Counnon mechanism D, usuali) Pulled a iuastor switeh. Each of. the` lino switrl'io has anQeSH to a nunilner of trunk-z` eat-l1 of which lcacls to a connector Switch H." nti alan, through roneleusors. to a :lo walled mondana lino switch (Fiff. 2). The secondary switch C' is similar in its` operation totho lino V@witch Q and is controlled ln' a master su itch D. The ser ontlary switch C' hau necesa to a pluralitj` of trunk-lines` leading to the niain ext-lullige. Whore nach onu terminates in a so- -alled til-5.a selector switch The tirata ueloctor E luv` access to trunk lines leading to second selartors F. from whieh trunk lines leail to c0n noctor switches H (Fig. 3). At I there ia shown a busy signaling niavhiue. and at; L a ringing oni-rent, generator is ahown. Tho nuhstation A2 is' provided with a line switch t niniiiar to that of snhatation ,3... One or oiore batteries B are provhleil. enel; having;- ona tvrininai grounded for the pur-poso of Supplying current for oi'ieratii'xfr tlm yn'vitol'inu` and for talking' purposes. The branch change (Fig. l.) is nlm provided With a ringing' rurrent generator L and a lousy signaling machine l.

Fig. Al Shows tho oasential features of thi;- nxas'ter `Qwiteh l) (Figi. 1i.

Fig. 5 is a diagrammatic iilub'tration of tho arrangement of the switches in a complete Systran.

The automatic Snhstations ma)- be 0f {In}Y suitable or approved typo. As hora shown. the substation A comprises a reoeivor 2t), `oviteh hook EL impulso wheel 22, transmitter 23. iniluotion coil 24. ringor 25, ConilvnS-er QG und impulse aprirlol i' and 'lao witth hook controls tho substation bi1 i-uits through tho xnodium ot' the cani arm 25) and springs 3U, 31 and 32. When tho re @Giver is on the, hook the arm 29 maintain Spring 31 in Contact with Apring 3:4, thm` bridging: tho ringer and Condonser lo in serios across the line conductors 33 and 3 their the rurreivor is removed the hook iu forced upward by a spring (not shown), allowing' the spring Si. to disngrage Spring 3;

and come into engagenientg with Spring 30. B3 this notion the rircuit ol the ringer 25 opened :nul :i bridge eousieting of the trunsniitter 223, primary Winrling of induetion Coil 24 und` impulse Springs 2T :nul 28 closed, across the line conductors 33 and The impulse wheel Curries upon its periphery the impulse teeth and is eecfurrol lo u sliuft 3G, to which there is also moored a dial (not shown ringer holes. When the dial is rotated forwirdH :i certain nunilier of toet-h (correv pending to the iligil milled) uro znlmnrenl pilot the ruin 37 upon the end oli the spring Si'. but with no ell'rct upon Suhl spring. When the dial i5 released it i5 returned to normal position., together with the impulso Wheel, hy u Spring (not shown)` AS each tooth paiwes the cuni 37 (lui-ing this; buck ward motion, the spring 2 ie forced out of engagement with the spring 'le' to open the bridge neros's the line.

The line Switch C und master switch D ure of the general type disclosed in British Putent No. 2.6301 of 1906, and in the 'Western f'iflfcfrm'uu of Chicago, Illinois. ot' January 12208. As here shown, the line switch C cousine; essentially of i plunger not shown) uituclicil to o plunger arm 38, and u magnet ill). lVhonrthe plunger arm 88 is attracted by the muguet the plunger is forced into bank of apringigs1 :mijl forros the springs 4l),

lland lf3 into Contact with the springs 4l, 13, and 417. respectively. The magnet 39 is: composed of four windings, u pulln winding u eut-roti Winding 49. u line whirling unil :in :iuxilierjv Winding 5l. "l'ho uuiojnetir rireui of the winilingp` 48 :nul it* is separate from that of the wind-- ingo: ill :nul 3l. The pull-in winding lS is for fluiiurposo of :uti-:uiting the plunger imo 35 to foire the plunger .into the bunk. 'l'lie eirrult of' tho winding -l-R i3 rontrollefl in' the milling ulwrilier throng-li the me- -liuui el tin line winding" 50 unil armature Si?. The winding 5l. prevenls the armature 52 from tolling herir immediately upon the lvinerfrimiouui ilu winding Jill. The outol winding i9 is provided for the purpose of holding; the pllingor arm in an oporatro' position und for @verering the eut-off :irmriture 53. If the winding 19 iu energized while the orlntnre fill unil oliniger nrin 3S ure in an operatori poaition, liolii the :numture and plunger arm will loe hohl in tine po sillon ritter llie uiniling le, is llenrrgixefl, but it the winding 4Q i@ vriei'gifmul while the armature D3 und plunger urlo lll are in norN nml position. only the urnmiure .'33 will lie operutml. :ie the Winding 49 is not is strong as winding 4S, Although only one sel ot' Springs L10. 4l. il?. 3. 4l, ll, 4G :nul iT is lshown, @noli lin(J Swilch (l i-- provided willi e hunk comprising! u number ol' Sui-li ,sete 'of springs, euch set forming the terminal of :i

) provided with Leesisi trunk line leading to a secondary switch C, Euch trunk is niultipled through ihr corro spending nunk iront-acts of n group ol' switches (Y The plungow normally rest in locking engugonient with u plunger shaft (not shown), and through the nieiliuin thereof are always held oppoite :in 'Mlle trunk terminal by the monster switch l).

KThe muster switch l) consists essentially olf u motor magnet 'which operates the ratchet wheel in?, circuit controlling roluys Ml, 5o and 57, and two banks of Contact fr uml. a euch moiuprising a number olV iii-'livifluul contorto (one tor euch trunk) and e common segment The wipers 59 and 59 ure adapted to elwiijifekeep Sonie one olA the infii Avicluul contacts o1 @zich bank in elet-trivial connection with the common segments. ,ly u suituhle mechanical connection the rotary motion of the ratchet Wheel is tninsuiitu ted to the plunger shaft to give Suid. shaft a reciln'of'uting motion to move (he iillo plungers 'backend forth in front of the benk terminals. To the plunger shaft there is oleo secured u. ouin 6) having on its surface :i number oi circular openings which ure adapted. to be engaged by the pin ill upon the end of the armature G2. The openm inge inthe can: 60 are so spaced that the pin G1 can engage an opening only when the plungerq that are in engagement with the plunge Sliui't ere in a poeition direetly in front of :i benk terminal.

The connector switch H is of the general typo disclosed in the Unit-ed States Letters Potent No. 815,176, granted March 13, 1936, to Keith Erickson and lzhrieloion,y but, here Shown, is modified to operato in conjunction with u two-Wire systexnutlmt is, o. system in which no ground connection is; re quired ut the Sub-station for controlling` the automatic ewitel'ws. Among other detail?7 the connector comprises a set of wipers Sii [il und secure-,rl lo e shaft (not shownl which has e vertical motion Controlled liv the vertical magnet {il} :ind a rotai'- filmini. controlled b r the rotar;- magnet il?, T'lio nsuul sidi.- ewirrli. izoniprieiug the wir erA (5R (il), 70 und 7L is controllml by the private magnet TQ in n well known nienner. The run-rulion of the switch controllori in' the rolling; suberriher through the medium ol' the ,louble-wounci line relay 73. lileans for releasing the oonneotor ure provided in the release n'liugnet 74, which ifs connected to buttery through springs und 76 only when the Switch @huit is out ol' its norn'nil position, A, boclobridge relay)r 7? is provided, through which the called substation is provided with. talking current. The ringer relay 7H provides ineens for connectirir the gruorntor L with the culled line.

In addition to the usual equipment the oonhector H' is rovidod with relaye 'T9r` S0, Sl and to ena `le 1t to operate' in ronjuuetion with my improved trunking system. The relays 81, 82, 83 and 84 are Slowneting relays 1'. r., relays that are slow to denergize after their energizing circuits have been broken.

The busy signaling machine I comprises an interrupter which interrupts the current through the primary Winding of an induction coil 85, thus producing an alternating current in the secondary winding.

Thel secondary switch C is of the same general type as the line switch C, its magnet 86 having only one winding, however, which serves both as an operating and holding coil.

The selectors E and F are of the general type shown and disclosed in United States Letters Patent No. 815.321, granted March 13, .1006, to Keith, Erickson and llrielrson, but, like the connector H', are adapted to operate in atwo-wire system. Like the connector, the selector E comprises a set of wipers 87, S8 and 89 having a vertical n1otion controlled by a vertical magnet 9() and a rotary motion controlled by the rotary magnet 91. The usual side switch, comprising the wipers 92, 93, 94 and 95, is controlled bythe private ma net 96. The release maginet 9T and line re ay 98 are like those of the connector H'. The selectors E and F are proi'ided with the` so-ealled connector releasethat is. the mechanism of the switches is released immediately upon the energizzn tion of the release magnet rat-her than upon its deenergization. as shown in the said selector patents.

The connector H is similar to the oonnector l1', with the excejjition of the relays T0, 80, 81 and 82, and with other slight modifications of its circuits, will appear from tln` description of its Inode of operation.

The operation of the apparatus employed in establishing cminection between two substations is asfollows: It will be explained, tiret, how the subscriber at substation A may operate the central ol'iice switching apparatus to establish connection with tl e subscriber at substation AL', the num er of ,which will be assumed to be 1n order to call substation #22:20, the subscriber at substation A removes the receiver from the switch hook. then inserts a finger in the finger hole of the dial, rotates it until the linger strikes a stop and then permits the dial to return to normal position. The operation of the dial is then repeated for each ot' thr remaining digits. lVhen the eeirer in removed from the 'nook the spring :l1 is allowed to disengage spring :l2 and to engage spring 30, thereby closing a bridge, eonsisting ot' the tranelniiter 2li, primary winding ot the induction coil 21 and impulse spring 2T an $8, across the line conductors 351 and 3l. l'hen this bridge is closed arrose. thf lint, it furnishes an energizing eircuit for the line Winding 50 of the line switch (l. This circuit extends from ground ir' through springs 9T and 08a, line 3l, springs 231 and 30, impulse springs 28 and 27, primary winding of induction coil 2l, transmitter 23. line 33, springs 101 and 102 and winding 50 to battery lead 100. The winding 50, uuon energizing, attracts tho armature 52, ulxieh forces sprino` into engagement with :spring 9T, thrreliv closing i a circuit extending from ground G through springs 97 and 09, windings 18 and 51, Contact point 103 and armature 62 to battery lead 100. The winding 48, upon energizing, attracts the cut-olf armature 53 and the plunger arm PH. The armature 53 operates to separate springs 101 and 98*l from the springs 9T and 102, thereby Opening the energizing circuit of the winding 50. The armature 52 does not fall baci( immediately upon the denergization of the winding 50, but remains up for an instant by the current flowing through the winding 51 in series with the winding 18. 'hen the. plunger arm. 38 is attracted it thrusts the plunger into the bank and forces the ,spring 101 into contact with the contact point 105, thus sln'nt-eircuiting the winding 51 and causing it to denergize slowly, thereby allowing the armature 52 to fall back. The falling back of the armature 52 opens the energizing eirruit ot' the winding 1S, but not, however, before the winding 19 has been energized. as will be explained, to hold the armature 53 and the plunger arm 38 in their operated positions. t the instant the plunger ot' the line switch presses the bank springs 40, 12, l1 and 11,3 into engagement with the. springs 41, 13, -15 and 4T an energizing eirfguit is closed through the Connector line relay T3. This circuit-,extends from ground (if through the springs il and 45, winding 10G of the relay 73, conductor 10T, springs 13 and l2. line 3l, thence through the substation and over line 33, springs +10 and -11 and winding 10S o1.E the relay 73 to battery lead 1110. thence through battery Bto ground (i. Ihe relay T3, upon energizing. shifts the spring 110 out o1? engagement with the spring and into engagement with the spring 111, and t'orees spring 112 ino engagenn-nt with spring 113. The engagement of springs 110 and 111 closes an energizing circuit through the relay 82. This circuit extends from ground (l2 through bank springs 1-1- and 45, springs 110 and 111 of the relay TIE. relay S2, Springs 114 and 11.3, conductor 110. contact point 117 and arniatuul 11S to battery lead 100. The relay S2, upon energizing, forces spring 121 into engagement with spring 122, thereby providing a guarding ground over the private normal conductor 1:23 to the connector pri- Yate bank contacts of the calling line, and closing an energizing circuit through the winding l?) to maintain the, line Switch C in an oprrzatil position. The engage-,manliof Springs: 121 :nul 1L ol 1h:` relay @El :i150 flows nn vnvrgizingg ril-enit through the magnet 5415 of tho wtfonilnry Hw itch C. This (-irini'l ixtunt'k l'roni ground (i3 through bpring 121 unil 111:3. 12-'1 unil 1125. nonilnrtor 12o, wlnringn lill nel 12S unil iii-lignei.. 8G to mitm-V li-:nl 1111i, Thil nnigrnt Sli, upon en- !rg'izing, nrnith l'ho nrlnailnro 129 and plunger arm 12.511. The :,trnintnrr 149 operates to .svpnrziu v-pringri 12S, lili' :1nd 131 und form: ,spring 1% into rngngwnent; with spring 1152. l`lw plnngir nro; 130, upon boing nltrnrlwl. lorrnn it plnngrr into the lmnk, lori-ingr spring 133, 135, 137 :and 139 in'io rontncl with springs 131. 136. 33 and llo. r'hiimrtiiivr. When 'he Springs 133 nini 15." ongngo the Springs 131 and 13G,

rispvrtirclv, tlnL inw ronncction is nxtvnded to Ihn lirst soli-olor 1C, 131101911)l closing a circuit extending- Vfrom ground (1* nl; the Selecor throng-h ilnwinding 111 of relay 9S, nihswitch minar 1111i, trunk' voniluctor 142, lmnli :springs 13. unil 135, conductors 113 :ind 11. springn 113 und 112 of relay 73, lmtn windings nl' rrlny S0 in Sorlin-1, conductor l-lylmnli j1rings and 131. trunk mnilnc-t'or 11T. @illu switch wiper 112 :md winding 115 olf the relay 98 to the batt/cry 1mi] 12o. Both ri-lnys 9S und S0 are onergrizoil ovvi: this uil-unir. The rolny SU, upon uncrgizing. forros lilo spring 1118 into conmi-t n'itli. thv nin-.ing 1111, tlnrchy closing n hohling rirnnil through 111e magnet S6 of llnf noronilnny nniti'li C. This circuit BX- lrniln 'from Ironnil G through 1hr, springs 11.51 nil 145,. winding 150 o1` the rolny '79, conilnior 151. wringh` 1552 :m11 128 :1nd magnrl- 13 i 11m lti'lirry inail 1110. The current flowing ovir thv rin-nit just traced mainlnilm 1in li wfilvh 1" in .ilo` oprrnril posh tinto :lnil :ihso .ili-zn'i'iis; thvy rilny T?, The. rrlnjv T51. npon ixnvx'g'iynrig, opnrnlrs o shift tho qnin-i lllont of vngng'i-nxrnt with the spring 11.3 unil into ungngeniont with the lining 1.3;?, -nui lo shil't tln` `spring' )l2-1 ont oi' Qngzigunwnt with Ihr spring 1225 unil into ingnzgrrnn-ni W111i. flir- I'll|;1` 153. The mr f fngoni-enl ol' tlm spring; 111 :incl 152 proriilw` n nun hnltirj" connection for the relay gli. to pri rrnt thiilrni-rgixntion of tho szlfl rrlnr n'lwn the :unmlnro 11H disungages gontrn't joint 11T nil-'m Thij opirntion o1 the nnizli'r :nilrh 1.3'. The .shifting of the` Spring 127i iliu-roniwil the gronntl G3 from thi ronilnrtor lcanlingl to the Sirig'omlary :niirh 1'." :nul glows 1 ciri'nit through the, winding' 151 nl' tho rel-.1y T1), Thon thc rrlnj; 13h of 11nl solvCtor 1*) is enrrgiziil. as pre- \,ion,-,1 rxjrninr-fl. il operates to (flowr a cir-- mit rxh'niling from fronnil (ii through tho hir-rings ,15h :unil 15V :mil rvln); 1,32' to the, lm'ttorrlvnll 121.1. l`1nrvlny 15T. upon eni-rfiriim4 unil hy shifting' spring 15S) out of rngagenwnt with the spring 101 and. into en- ;rngrrnelit with the Spring 16), Shifts tha cimneution ol' 111e impulso spring 158 from [liv rolwm; nnigner 9T to 1hr; vertical magnet 5111, thrrehy plating the selector ,E in position io receive the impulses for the first digit. of theA ile irod nnmbor.

At tho instant thc mink springs; 11 unil 15 nre fori'oil int/0 rontlnt by tho plunger of the lino switch C n cironil; is flloseil throlwh the relay 56 oi rho master switch D. T1115 rircuit enlands from ground G2' through the springs L11 und 45, innstor switrrh bunk conmet 162, Wiper 59, segmont 555 :intl relay 5G to 'the battery load 10U. 'lnz relay 51. npon energizing, (.losf-.i-z :tn energizing circuit throngli the looking rclny The. relay 57, upon onorgizing, attracts its nrnmtnre 62, which witlnlrzins he pin lll from the Cam G0, unlocking the plunger shaft, and 'sloot-r; a, cirsuit through 1h13: operating magnet 51. This circuit extends from gronnil (ii through the magnet 5l, intnrruptor sprl H33, rontitc point 1(51 and .snnnllnre 62 lo the battery lend 1GO. Since this circhi# nulndrs the inlturruptor Springs b, the motor magnet',` 54 Will continuo to oljnzrsttiin a nummer similar to lllat of a bugzi@ iis long in; 'the armature remains in Contact ith `tlmy point 164. Thin oiitnned oimrntion of' the magnet 54 givin; to thi-3 ,rntrho wheel .35 :intl the plunger shaft :t rontinnonbmom-0n lo more the idle plungers foward the next trunk. After tho plunger shaft hns moved. n short distance the wiper 59 passes oil the rontinfr 1132 :nul ullont.` the relays 56 :nifl 5T to deinvrgize; but since tho anni 1513 has also boon moved tho :1i-maturo 62 cannot ilrrfp hns-lf until the next: opening passes nn-vr tho pin 151. Ars Soon ai: this; next opening ruw-hof; n position directly under the pin 131, ihn 'n nin li-ops into this opirnng, thus lori-jr.,D tlm plnngcr Shaft against further rotation. nml :illows the armature 15135 lo disnngngrn the point 164 so :is to optan tho operating sin nit of the magnet 1f tho next l'rnn; after the one occupied by the Switch C hail born busy, there would have been :t gnuriling ground po'mntial upon 11nl :writ Contact rngagri'l `by they Wiper 59 afifr heaving tho Contact 152; ronnqurntly, thi?` relays; 5h :11:11.57 wonhl havn remained energizvd while tho next opening was pzxssing thi? pin G1, thnQ, ruimingtho plnngers to lio i'arr'ici past the '11H55' trunk to an idle ono. 1f; will ho sven that as long as the .master swit'rh D is operating, the nrnmtnre 62 iS flisongngmfl from rho contact. point 103, thus dis# Connecting! the battery from thc Winding 48 of all the lino Swirl-lies C to werent the opor-- ation of :11151 switrfh while its plnnger is in motion. When ill@ lmnh springs; 139 and 140 :tra premiar-fl into fontinft hr tho plunger of the svrinnlslrjc nwiwh (1. tht mister switch AD' npr-rains in [liv `:noir mnnnvl :is the mnotor switch D to mlvancv 1hr. iille plnngcrs to :in lille trunk. While the muster Swilrh D ,is ngwruling? the separation of the armntur 11S frmn the contant point 11T disconnects tho bnlory from the relays 8:. oiul th@ connut-,torn H lo prevent the secondary Switvhes C troni boing uperutml while their piling-vrs :mi in motion. The, disengagement of the urnurluin 117 from the vontnvl point 1liwlxil tlvy luna-tor Switch ll' is opvl'uing also nponh` blu circuit of tinA1 rclny 291. The relay F391 is :i \\'noting relay and (loom1 not huw timo lo flnliifrgizo if tho inuswr Switch D winply hun to paus Jfrom one; trunk to the iux.. ll". limwrilr, the muster switch hns to purs ow-r .1 uumlnr ol' busy trunks; thv cir unit of ihn rulfiy L01 is opened for n Vlimgur tinur nnfl tho relay ilvnrgizfs. Thon thu rlur 2li-l (lnliziuigizcs il: grounds the ronifliu'-y tor L'UJS hauling izo the infflividuul segments ol"` the auxiliary ninster switfh bank a' of the uinstrer mitch D. It ull the trunks from the limx switch C load to the group of svrondnrjr sn'itfln-.i Ponti-filled lay the niuntur Switch Il. :lll the iinliriclunl 'ontzwt of the hunk n' will l|@,-f-iiuiu=f:tod with lli@ conductor 1.13. 'll'nf 'fnnniou auguri-nt, ol the bunk o in von 'zwi-lud willi n rvlay 51111" whioh is Similar to ilu inlay 113; mul. ronequuntly, whnn tlu ouilnwmr Lll i grerunfled the ruin.)Y Nils is wrwrgg'rfzml und rauw the master i-1\\'iirli l) to opcwxtu in llnf Sunni. murmur n wllin tho CnnV4 luvh, nl' llu lmfil: if. :iro lflfniiuluil. (lt roursl, un hun lli-un wir "unl, ,iliill tho nusai'vr su'irrli ir in opor; ing no lim` switch. C cnn hc tuuu-anni. tho lrunlas4 from they primary lu'ilf'lum l" 'Irv slinfrihinrfl nrnoug'n nui'ulwr of" groups nl* wuunllur): swilclns C, izn'li. inwn'llliil willi u Si-{nirzzlu nmntvr :iu'itflu thu f'oniliu'liluf lfi will ha mnnlwtw with the* minimum i=enir.-,ponilingr only to the trunlib' Whif-l` inurl io tlm group of Lintonclnry su'ilrnwu uonifollwl h v the ninalir Swirl/h 17)". ln 'this` u: u tin; grounding of the Conductor fli will pruvunt th@ nmstir swilrh l) lronl r r'o|] in; on :my of thu trunks' lz-zwliiig to ,\*rlun\1 uon'trillwl lay tlm mustn' sur ilfli 1), lun will not. pruvmu' it from @nipping un any milan!" il'iml. i

Thu ffnfgoing il# tho condition of tho renY tml oiiirv win-hing apparatus i; izuwliatvly utlvr llw runnrrnl of thv rwivur :il ilu? @allV ing Suhfxtnlion unil huforu thrcniling ilfviro fnwixitml 'For tho iirht digit. f; the im- 'giulw uluwl 712 rvtnrns to normal position nl'iir hrung rmutml for the first digit (9), il; loi-w1 #lin `*gn-ing; 2T out of ungugmnunt with in@ Spring lirico, thm (Winn opening the vnvrgi/ing rirffuil of thu uunnmtor line roluy TP.. Il vill he sum1 that the relunsu rw luf SI5 of thu connfvl'or H' is normally connintwl to hul'luly through 1h11-, cmnluCtor IGF :unl umgfno 25 of' tho uncoiuluigv swjtvh lui! u'lwn lla(- ,kwitrh C in olivi-:alud fili@ mir nrr'lion is ln'oliou. thus prvrvnlinf Ihn rvluy FC5 from vnorgizing. Since ilu rei-luy Sil in not energized, the operation of the relay 73 'doos not (-:nio the connnrftor to bo operated. It will he rununnhuruil that rho energizing circuit of tho relay 80 mul of the line relay 9S of the selector E passes through the snfingg 112 and 113 of the Connector linel rflay Now, nach lime thv rolny 73 flenergizvs in response lo lho impulses from the: substation, the separation of tho Springs 112 und 1123 hreuks the energizing circuit of tlm roluyn 80 unil 99. T110 rilny 80. upon (luunergizing. i'lerinitfthe), spring 1418 to (lisengngthu spring 1l!) nml to vnfrfngo tho spring 1G13. The li igzigmnvnl olf the ,sp2-ingu 1-19 und 14! disconnects; ground (l5 from thc winding 15G of the relny T9 und nmgrnel Si; 01 the switch C', lint ut the sume time u new Circuit is closed through the muguet Q6 by the rolny T3 The holding circuit ot' tho magnet S6, during the time tho relay 80 is (lonorgized, extends from ground G2 through the bunk spring ll und l5, Springs 110 und 1G53 of tho relay T3, thence through 'the Winding 150 of the relay 7l? and magnet l?? to the hattsiry. fis previously traced. The simullanoous lox'im'gization oit' tho ro :nys T3 und Si) also closus n circuit @Xtfnding from grounfl'G? to :nul through the springs 110 find 1G?. ns'liufst traced. thon@ through flu` nin-ingu 11S nml 166 of. lhe relay 80. rplny 91, Conductor 397 und hunk Qpringn 13T and 13S oi thu switch C" to the buttery loud 100. Tho rulli); 81, upon onvrgizinfr, disconnects th@ conductora` 144- nnil 113 trom the conlflnsur 16T :unl 1118 and Short-cirlnil'i thu 100 winding' 169 o1' thi'. relug; S0 to rluoruuso the rvsiutsmm Ol tho bridge :w1-ons tho condurors; 143 und 114 while the iinnulufrs aro being rfpclatnrl to the relay 9S ol' the uvlertor E, The rvlny 81. lining u Slow-.zwting rvlny, 105 in onergizml by thv first impulso for ouch (lign, und rclnxairm in its onf-rgimwl poition until after ull the impulsnsi for that digit have hinn transmitted. After ull of the impulsos for @zich digit` have hQon trunsm'ittuil 110 the relay rleunrgizes :mijl oonnuffte; tho talking conductors 14.1 mui 113 through lhu conllenlers 167 :nul 168 to llm culling linv.r :nul also rumorea the short-rirvuili of thv winding 1??? to inffrnnue the 1-rsi innro of thu 115 hriilgr- .@:ulciontllv to provnnt the tulking;r rur rents from passing from omI nido of' the liney to the uti/afer. lihu'li timo the rolfly 73 ilumwrggiznf; it also upenn tho virouit of the reilay 99, hut tlw relay 9i?, boing slow-acting, 12 don not huw time to cloinc-rgico during this rnomunlury intnrrnntion ol' its Pircuit.

Euch time thu who; 99 ol'- lluf Selector E definirgizos, thu spring' 155 flisongugcs thu spring* 1516 nml Qngngirnthu Spring* 13S. The 125 ruluy 157. heilig: n slow-:ietng relay, loes not huw tinu to clviinurgim :hiring thuy time thv :un-ings 153 nml im uw flisvnmiguil. unil. fo'rislfgfwntlv. ilu* vnf :|;funwnt @if the springs 1:19, unil 155 glows :in onergizng circuit 130 ihr; iii verfilmd muguelf'i'i. i`liib'circuit exieuw: imm ground ii" ihrough the Springs 15:3 und 15Sl 15S und IVM. rel; f 1Y0. muguet lill und 'sillv huiiei wiper Uil lo the lmtl'ery lend l. filifii lu; iliglii (':ilhil iS tlm verl rail muguer 5H) receives ihr iinpulnes over the f-irfruif; jus! irured :sud operuhfs to mise `he l :rfi und u'iiieru HT. E1n und Si) two stops ro u posiion ug .ie the ivooud row or level of iurul om: mi .ia yion :le Lhlf slush lowes iis; lowest im lion the 1x1-ni 171 per mit@ 'the spring 172 to enguggje :he spring 1.73 no us [o ruiniert the release, nmgneu il? with ille buttery li, The rijlzfy 1TH: which is inrluded in ilu? energizing' oiriuil of the rei-tieni iuugneh in energized `hy the first impulue and openden to oloso u ifiriuit oX ten/.ling from griuuid G through the springs 17'1- unii 1T!) :ind lie private muguet 9G to ille buttery lend 121|. Since the relay 170 is u ulowfiei ing,T relu)` ile: rireui, is uur opened hing; enough lo permit il to rieflnergim: until ailier flu l imi-uhse u; trrinsruiftcd to the verhrn iu wil Vfl-ien the relay 1T() der ein; meitam; it nin-iw ilu: fii'euit of the private muguet EN?, which iu in turn deiinelgized mill allows the hide SJfilefh lio p.; tio second limbiioi. The niowriiien of ihe @ille switch u iper J5 from h'rut lo eeeond i'ioisiiiou shifts ilse imiter); ron'lieri'ion ,from flic feliiieail iii! io h@ roury niuguer 521 ilirough luf-,J iiii. ller rotinr umgurt i? iS ex'reuding ifroliiul fr" :l :ugh ilu' iniinrugjitei' i unlgmft `Fl reilly lili. ronlurt Y um PTH simi :Hille swili'h wiper 9.2 lo the ml'ieiv lend 1%. The inuguei 91. upon 'ing` oporufos To press down the urinalua-e of :he prirzkilmuguet roiiuuthe wipers one utep und tu uren its sun rireuit. lVhen the rir'ui oit ho roiarj.' muguet; is thus opened the: miliariy :immature fails luuk, und if thu iii-,t ruoli engngeil h v the wipers is noi :drei-idr iure; he primr muguet :mmv hire iuli i- :ilffi und pei-mils liao sid@ .-urilel! lo in s from muni lo ihird guirsiliou. rV iruuli engug'ril hy the eelor wipers ii, falreeexiji' lulsj-,f on :looount of hazing' heen :en oli lijf uomo other switch, he privul'e wiper 97 indu the iirsl. priv-.ile iifmh roulant ifrouuclell. when ille private wiper HT illus, eujgufz-,Q u grounded rontuot ii #iones :i eireui emi-riding through .the iside :switch wiper f ilmituut. ll und privato muguet lll; lo lhe lini'iery ieud 120, The prirsiiiemuguet lieconieu energizwl hy the olouure of this. eirclii. und loein; the side switch. ineeeond posilion iii muinhiiu the lmllory eonuelfliou oi' the roiui'ynmgnut. The ninguei 311 will continue lo rofute the, wipers glei hy Siep until rho priyuiu wiper' finds the inui'grouuded ronlzui of mi idle Li-unl:` whe-,n She primis muguet fili deiinergizes :1nd iihuvr: x'iae `idfm. urli lo im# into lliird posiiu. 'lhe relay 175, which is energized in im ,-Miylwi @Longoni-cl mei :l onwil ihm).

seriesy with tho rotury nmgnot 91, is :i slow` noting relay und remains energized for u short time after the Wipers are rotated the lust step. (lon. ouently, :it tho instant the side :mitch pass@ to ihird position u gruzu'd ing ,Ljround poteniiul is established ai the nele-@tor privato hunk contacts of the P'ized trunk. This guarding ground potential ex te du from ground fi tlmmgii the fiprings iol? und 1F31.y continui point 182 @ide su'iloh wiper J1 und private wiper Si' to lhe contact upon which it, is resting, 21ml thence to tho corresponding contarlo in the hunk of auch of the selectors whirh have access To the trunk conductors 183 und 184?. The Inovemeiil. of the side switch wipers 92 und 93 from second lo third position disconnects he relu? JS from the line und extends the. nonneetion over the conductors 133 and 184 to the seeond selector l". W'hen the conne@ lion iis thus extended to the second Selector ille line relay 185 is energized in the saine nimmer :is was the, relay 9S when the connection uns extended lo lhe first seleetor l?. The relay 'iS open-nies in u mam-loi' Similar to the relay 9S to close the cireuit, of the releuw reluy 186. The relay 186, upon enorgizing'. furnishes u newV guarding potential for the seized trunk. und :1S soon :is the reluy 1753 ol the firsi selector deinergizos, u holdinff rim-uil is closed through the ro'iouse who 1i This oil-cuit extends from ground G through ille side swilzeh Wiper 1ST und springs 1518 und 18.() ofihe relay 13S, privado hunk Contact'. sind wiper 87, side swilrh wiper lll, Contact point 182, springs 181 und 190 und relay 157 to the battery lend 120. This eil-cuit through the relay 157 is closed hw 'fore it has time to duiinei'gize after its foi'- iner eireuit is opened by the deeuergizntiml ol' the relay 98 when the side Switch passes to third position. 'It is thus evident that 'lhe relay 176 must be quicker than the relay 1,37. the only function of the relu): lili lacing te. furnish n guarding potential to the private lundi eonfnots duringr the iii'ne @lansing ni'tur he side switch passes: fo third position` und hofore the relay 181i of 'the second solevtor energizes.

When the substation oidiing doris@ is operated for the second digit the line relay IRS ze piinrls lo rho impulses in the Same :hunner :is did the relay 98 of the selector E, lo muse the Second seleetrrr F to extend the eomierlion lo un idle counoetor 1l over the rmuluotom 1.91 und lil-2. ihm the connection thm` extended to the 'mluellor the, line reluy 194 und release reluy 195 ure energized in the sume, manner :is the line :1nd Pelouse, rel-.Lys nl the selectors. The energizution of tho relouue relay li provides u guarding potential for the trunk lending to the erumeclom und uiso rloseu u holding' circuit ilirough the release relays 15T und 186 of the selectors E and l". Thi circuit` extends from ground G10 through the side switch wiper 190. springs 19S and 197, conductor 1923, private wiper 199, side switch wiper 200.` springs 201 and 202 to the con4 ductor 203. From the conductor 203 one branch of the circuit extends through the rela)Y 1.80 to battery, while another branch passes through the side switch wiper 187 (which is now in third position) to and through the first selector release relay 157 over a circuit already traced.

The connector H is now in position to receive thc impulses for the last two digits of the desired number. When the substation calliing` device is operated for the third digit 2) the relay 73 of the connector H opel ates (in the manner previously explained) to repeat the impulses to the relay 194 'of the connector H. Each time the relay 191 dcenergizcs it closes a circuit extending from ground G through the springs 205 and 204` 200 and 20T (the relay 195 remaining ener gized durinpr theV time the relay 194 is 0perating). vertical magnet 208, side switch wiper 209 and relay 210 to the battery load 120. Since the digit called is 2 the. vertical magnet, 208 receives two impulses over the circuit just traced and operates to raise the shaft and wipers two steps. ,As soon as the shaft leaves its lowest position the release magnet 211 is connected to battery through the oti`normal springs 212 and 213. The relay 210, which is included in the energizingcircuit of the vertical magnet. is energized by the first impulse; but being a slowacting relay it does not have 'time to de energize until after the last impulse is transmitted. The relay 210, upon energizing. operates to close an energizing circuit through the private magnet 214. This circuit extends from ground G12 through the springs 215 and '216 and private magnet 214 to the battery lead 120. Then the relay 210 deencrgizes after the last impulse is transmitted to the vertical magnet it breaks the energizing` circuit of the private magnet, which in turn denergizes and trips theiside switch to second position. When the side switch wiper 209 engages its second-position contact point 217 it connects the rotary magnet 218 with the battery through the relay 210 in order. that the rotary magnet may be operated by the impulsos for the last digit (0). Each time the relay 1.94 denergizes in response to the impulses for the last dipit` a circuit is closed through the rotary magnet 218. This circuit extends from ground fi through the springs 205 and 204. 206 and 207, 219 and 2?()` magnet, 21S, contact point 217. side switch wiper 209 and re- .lav 210 to the battery lead 120. Since the digit called is 0. the rotary magnet receives tcn impulses and operates to rotate thc wipers 221. 222 and 223 ten steps onto thc terminals of the line #2220. Since the, relay 21() is also included in circuit with the rotary magnet 218 it operates in the Same manner for the last series of impulses as for the previous one`r to cause the private magnet 214- to trip the side switch from second to third position after the wipers have reached the contacts ot the called line. lVhen the side switch wipers` and 225 reach their third-position contact points the connection from the calling line is extended through the shaft wipers 222 and 223 uto the called line. When the side switch iper 209 entraves its thirdiosition Contact point a circuit *i a 't l' fic13 i i is c ose en cnt mg ioni giouni 1 t nongi the interrupter 220, springs 227 and ofthe back-bridge relayI 230, ringer relay 229, side switch wiper 209 and relay 210 to the battery lead 120. Since this circuit includes the interrupter 220, the ringer relay 229 will be energized intermittently until the called subscriber answers or until the connector is released. The relay 229, upon energizing, shifts the springs 232 and 235 out of engagement with the springs 231 and 234 and into Contact with the springs 233 and 236, respectively` whereby the calling and called lines are disconnected and the generator L is bridged across the called line.

lVhen the called subscriber removes his receiver in response to the signal the spring` 292 is shifted out of engagement. with the sprinw 291 and into contact with the spring 293. thereby opening the circuit of the ringer 290 and bridging the primary talking circuit of thc substation across the line conductors 237 and 238. lVhrn the primary circuit is thus bridved across the llne, or as `soon thereafter as t ie ringer relay 229 denergizes, it it happens to be energized at the time, the called substationi'is provided with talking current over a circuit extending;r `from ground G through the side switch wiper 239, Winding 240 oi= the relay 230` ringer relay springs 231 and 232, side switch wiper 225. shaft. wiper 223, line 238, primary Winding' of the induction coil and transmitter of substation A2, line 237, shaft Wiper 222l` side switch Wiper 224, ringer re` lay springs 235 and 234 and winding 241 of the relay 230 to the battery lead 120. The relay 230 is energized upon the completion of this circuit and, by forcing the spring 227 outl of engagement with the sprin 228, prevents further energizatiorr of the relay 229 after the called subscriber has answeredA and the two subscribers may carry on 8.11.1111- intcrruptcd conversation over the heavyon ductors shown in the. drawings.` As soon as the connection is completed with the called line that lino is protected from seizure by other connectors by a. guarding potential extendine from ground G through the side `switch wiper 239. relay springs 242 and 243 and private wiper 221 to the private bank contact 214, and thence to the corresponding mugrul relay :Zlll luv falla-Ii lim-li, il will be 'and 45', springs 110 and 111 of the ceive the busy signal until the receiver is hung up, when the switches will bc released, as previously explained.

The toregfoiiiar is a description of how the subscriber at substation A may call a subscriber at a distant exchange. It will now be explained how connect-ion may be, olitaincd with another subscriber at his own exchange, iVlien a subscribe at the branch exchange desires to call another substation of the saine exchange he does not call the regular number` but simply prefixes a certain digit (in this instance l) to the last two digits of any number in his exchange. For instance, it' subscriber 5000 wishes to call subscriber #5040 he operates his calling device for the number 140; if he wishes to call #5020 he calls #120, etc. Some certain level of the banks of the first selector switches of the main exchange has no trunks connected to it. In this ease it is assumed that the tirst level is the one which has no trunks, but any level may be used t'or thisqpurpose, it 'being understood that the number which the branch exchange, subscriber prefixes to the last tivo digits of his number must correspond to the dead' level ot' the selectors. lhen the subscriber at substation A removes his receiver to call #120 the switches C and C operate in the saine manner as previously explained to extend the connection to the first selector E. W'hen the calling,r device is operated for the first digit (1) the selector E operates in the regular manner to raise its wipers one step to a position opposite the first level of bank contacts, a'l'tcr which they are automatically rotated onto the first contacts of this level'. Since no trunk lines are connected to this first level, no circuit is niaintained through the relay S0 of the connector H after the side switch ot' the selector E leaves the second position` and consequently the relay 80 dcni-rg'izes Of course, the line relay 73 of the connector returns to its operated position immediately after the impulse is delivered 'for the first digit; consequently, the dciinergizatiou of the relay H0 breaks the holding circuit ot the magnet H0 ot' the secondary switch C. The secondary switch is immediately released by the deinergizatioii of the inagnet 86. The separation of the bank springs 13T and 138 by the witlidra 'al of the plunger disconnects the battery from the relay 81 to prevent. the operation of the said relay during the subsequent operations of the connector. The engagement of the springs 122-5, 12T and 131, upon the deencrgization ot' the magnet 86, closes ai1`en ergzizing circuit through the connector release relay 83. This circuit extends from ground G2 through the bank springs 4i relay 73. springs E262 and 263 of the relay 77, relay S3, springs 264 and 265, 206 and 207, conductor 105, springs 131, 12T and 1:28 and magnet S0 to thc battery lead 120. Although the relay S3 is energized over this circuit, sufficient current does not liow to operate the magnet 8f3. The engagement of the springs 20S and :60 of the relay 83 connects the impulse spring 10S) with the vertical magnet lili through the relay 8st, thus placing the connector in position to respond to the in'ipulses for the last two digits to complete the connection with the called substation. The relay 79 is maintained energized by the current flowing through the winding 1.51 duriingr the tollowing operations of the connectoi: Of course, the selector E is automatically released shortly after its wipers have been rotated onto a doad"" contact, because there is then no ,ground to maintain the relay 15T energized.

1When the substation callingr device is operated for the lens digit (i) the relay ilis twice inoiiicntarilx dencrgized, each ltime closing a circuit through the vertical magnet (Sti. This circuit extends 'from ground (i2 to the spring 110, as previously traced, thence through the spring 109 (with which the spring 110 engages), springs 268 and :09 of the slow-acting relay 83 (which remains energized during the operation of the relay TBE. private magnet relay S4, vertical magnet 0G and side switch wiper 70 to the battery lead 100. The vertical niagiictrcceives two impulses over this circuit and opfrates to raise the shaft and wipers (i3, 0i and (Si tiro steps to a position opposite the second level oi' bank contacts. The private magnet relay 8i operates in the saine manner as the relay 210 of the connector il to close the circuit of the private magnet 7". The relay 34 deiincifgizes after the last iiiipulsc is transmitted to the vertical magnet and opens the circuit ot' the private magnet 72, which in turn denergizes and permits the side switch to pass to second position`r tlnL-i'eby placing the rotary magnet 0T under control of the relay 73. Each time the relay 73 deineigizes in response to the, impulses for the last digit a circuit is closed through the rotary magnet 67. This circuit extends from ground (i2 to and through the springs 110 and 109, as previously traced. through the springs 208 and T200, relay 84, springs 270 and 271, rotary magnet fi? and side switch wiper 70 to the battery lead 1&0. The relay 84 bein included in this circuit is also energizec by the firstV impulse and again closes the circuit of the private magnet 72. The relay pulse is transmitted to the rotary magnet and again opens the energizing circuit of 84 deinergizes again after the last iiii.

iur

From the foregoing it will be seen that; I provide a system in which a subscriber of one group may call another of the same group Without extending the call through the main or central station. The contacts 4l and 43 serve as a terminal for two trunks. One trunk leads to the connector H and the other trunk leads to the non-numerical ./switch (1. Means are provided. as described, for preventing operation of the connector when the call is through the line switch C" and the selector E. In the selector E the `bank level serves as a means for preventing use thereof when the call is through the con nector. Bv the calling dinl at the .substation the calling subscriber determines which trunk is to be used, the one leading to the switch H or the one leading to the switch C'. These switches are controlled over line circuits including the tWo sides of the calling line in series. Duri-ng promotion ot the talking current, as indicated in heavy lines, the connector H" is connected therewith. but in an inoperative condition. By a connector I mean a switch capable ofopration in aecordance with two digits of the called number. By aV selector" I mean a switch capable of operation in accordance with one digit of the called minibarthat is.' capable of antoniatieally selecting an idle trunk in a predetermined group.

The arrangement of the switches in a. complete system, such as is disclosed in the foregoing. is, as stat-ed, represented diagrammatically in Fig. 5. In this figure therelnre. shown a number ot' branch or subexchanges, each provided with primary switches C, secondary switches C' and connectors H and H. To each subexchangethere is allotted at the main exchange a grou i of first selector switches E and a group ot second selector switches F.

that I yclaim as my invention is 1. In a telephone system, a trunk for local calls. a trunk for calls through another exchange or station, a set, of contacts serving as a terminal for both trunks at one end thereof, an automatic .switch for connecting with said terminal to extend a call over either trunk. automatic means for completing calls from one trunk, and means for conlpleting calls from the other trunk.

2. In a telephone system, a plurality of trunks. a single terminal affording access to all of said trunks. whereby thc trunks are connected in multiple to said terminal, andA an automatic switch allotted to thc otherend of each trunk' lor extending connection therefrom. each trunkcomprising a pair ot' roice-cm-rent conductors.

3. ln a telephone system. a plurality of talking trunks. a terminal common to all of said trunks. whereby said terminal is necessary for extending a call over any trunk. an automatic switch for determining the proper trunk for use in making any call, and automatic means for extending a connection from Said trunks.

4. In a telephone system, a plurality of trunks, a terminal common to all of said trunks, means for engaging said terminal to connect a calling line with said trunks, means controllable at the calling substation for electing which trunk is to be used in completing the call, and automatic means for exY tending a connection from said trunks.

In a telephone system, ailing mechanism for transmittirngr impulses for sending either local or trunking calls, a pair of trunks, a single terminal for said trunks, whereby both trunks lead from the same terminal, a connector at the end o1c one trunk for use 'in establishing local calls. a trnnking switch at the end ot' the other trunk for use in establishing trunking calls, subscribers lines terminating at said con nector. trunk lines leading from said trunkn ing switch, a first 'selector for each trunk line. said connector having a relay for controllingth'e said selectors when connection through a selector is necessary. and said selectors having means torprcventing use, thereotl when connection is necessary through the `eonnect0r.

l. In a telephone system, calling mechanism for transmitting impulses for sending calls, a selector. a connector controlled by said impulses. means for connecting with said connector and selector, and means in the. selector tor preventing continued use thereof when the call must pass through the conneetor.

7. In a telephone system1 calling mechanism for transmitting impulses for sending calls, a connector controlled by said iin pulses` a selector, means in the connector for controlling the selector when thecall must not pass through the connector. and means in the selector for preventing use thereof when the rail must pass through thc connector.

S. In a telephone system, calling mechanisxnfor transmitting impulses for sending calls. a terminal. a pair ol trunks connected therewith. a conliector at the end of one trunk controlled by said impulses` a nonnumerical trunking .switch at the end ot' the other trunk` a mn-numerical trunking switch for connecting with said terminal. a

selector, means in said connector' for con-.

trolling said selector when the call is through the Selector. and means in the selector for npreventing use thereof when the call is through the connector.

S). In a telephone system. calling mechanism for transmitting impulses for sending calls, a switch controlled by said impulses. another switch. means in the first switch for controlling the second switch when the call must pass through the second switch,

means for preventing use ot' the second switch when the cull must pass through the first switch, und menus for )'neventing use of the first switch when the call is through, the second switch.

l0. In n telelihone system. calling mecha nism for transmitting impulses for sending cells` :i conne mr controlled hy snid imv pulses. n selector, menus in the connector for controllingr the selector, means for preventing operation of the connector when the selector is operated to extend n cell, means for automatically restoring the selector to normal when the call is through the connector, und menus for (.'ontrolling the connector in accordance with the last Vtwo digits of the called numher.

ll. In n telephone system, calling mechanism t'or transmitting impulses for sending calls. a connector controlled by said impulses, n selector havingr a plurality of levels und oieruble to any level and having means for automatically releasing when raised to n piuticular level. means for renderingr the connector operative when the selector is thus released, und ineens for preventingoperation of the connector when the selector is raised to some other level.

12. A telephone exchange system comprising,r e combination connector and repeater, n. talking circuit from which the said combinntion instrument is excluded when used as u repeater, e. talking` circuit in which the seid instrument is included when used ils n connector, and switching means in said firstmcntioned circuit controlled by the seid instrun'ient when used as it repeater.

13. ln -n telephone system, means for forming n talking circuit, a plurality of conm nectors, means for operating said connectors, und menus for tenipornrily rendering the seme inoperative by the formation of seid circuit, each connector being operative in accordance with two digits of a. called number.

1. In e telephone system, a trunk for loool calls, n trunk for calls through another exchange or station, a set of bank contacts serving as e` terminal for both trunks at one end thereof, means for connecting with Said terminal to extend o call over either trunk, means for completin f calls from one trunk, controllable over the two sides of the trunk in series, und automatic means for com leting calls from the other trunk, control able over the two sides of the trunk in series.

15. In e telephone system, o plurality of trunks, e single terminal affording access to uli of said trunks, whereby the trunks ure connected in multiple to said terminal, and means allotted to the other end of each trunk for extending connection therefrom, oontrolluhle over the two sides of the trunk in series, each trunk comprising a pair of voicecurrent conductors.

16, In a telephone system, a plurality of talking trunks, trolhihle over the two sides of the trunks in series, n bunk terminal common to all of Said trunks, whereby said terminal is necessary for extending e call over any trunk, means for determining the proper trunk, for use in making :my cell, and automatic means for extending n connection from said trunks.-

17. In :i telephone system, a plurality of trunks, o, terminal common to all of said trunks, means for engaging said terminal to connect a` calling line with said trunks, automatic switches controllable over the two sides of the trunks in series, .and means controllable from theV calling substation for electing which trunk is to be used in completing the call.

18. In n telephone system, calling niha.- nism for transmitting impulses for sending calls, a pair of trunks, a single terminal for said trunks, whereby both trunks leed from the same terminal, a connector at'the end of one trunk controlled by seid im ulses, a trunking switch at the end of t Ve other trunk, subscribers lines terminating at said connector, trunk lines leading from said t-runking switch, n first selector for each trunk line, seid connector having a. relay for controlling the scid selectors when connection through a selector is necesary, each selector controllable over the two sides of a trunk in series, and said selectors having means for preventin use thereof when connection is necessary tl rough the connector.

19,. In e telephone system, a central station, a plurality of subcentral stations, subscribers lines termina-ting at the' subcentral stations, trunk lines connecting the subcentral stations with the c'entrel station, means for extending a call through the central station from a calling subcentrol station to a called subcentral station, controllable over the two sides of s line circuit in series, and means affording direct connection between the lines of calling and called subscribers of the same subcenitrel station, controllable over the two sides of a. line circuit in series.

2l). In a. telephone system, a central station, subeentral stations, trunk lines connecting the central station with the snboentral stations, telephone lines suhcentral stations, nnectors at the suboentral stations for connecting o telephone line of one suboentral sta-tion with a telephone line of another subcentral station, controllahle over the two sides of'a line circuit in series, and other connectors for connecting a calling line with a called line of the sume suhcentral station, controllable over the two sides of a line circuit in series.

21.` In a telephone system, n connector for' findingr the called suhscrihefs line, when the call is local. provided with a relay for re'- peet-ing the culling impulses when the call is automatic switches c0n` terminating at the to another at ation.` and moans ilulopenilcnt of thc @round at tht: substation for controlling Said connector.

ln a tclcphono hystcin. a connector. lucana for controlling saiil conncctor in accoialancc with thcv laat two digits of a cnllcill nunibcr. a Hclcctor, said conncctor having a rclar for controllingr `aaiil scha-tor. a trunk lincW a Inl a circuit incluriiirc thi` two `itlcs of Saul trunk line in aci-ica controllcil by sai l rc ay to control thc 4sclcctor.

Q, ln a tclcphonc systcin. a liuc, circuita conncctor.y nin-ans for controlling saiil conncclor. in accorilanco with the last two digits ol' thc callctl nunrbcr, over thc two siilcs ola linc circuit` in scrics. and a plurality of Sc,- lcciora. saiil connector having a relay for succcsaircly controlling said selectors.

"il, ln a tclcpllonn Systran. a sclcctor. a conoci-tor. nicans for connecting;r a calling` linc with said conncctor anil aclcctol. nicans in thc Hclcctor for prcrontiingl continucd usc thcrcof whcn thc call must pass through tho conncctor, anil nit-aim` at thc calling' subatation t'or controllingr thc aairl sclcctor nml miliicctrn ovcr thc two siilcs of a line circuit` in crit-s.

iff. In a tclcphonc Stom. a calling suh- `Rtation. a conncctor. a r clcftor ailaptcd to ha conncctcel thcrcto. lucana in thc connector Yfor controlling thc sclcctor whcn thc call mit not pa` through thc conncctor. IncanS in thc sclcctor For prcrcnting usc thnrcof whcn thcy call mustI pass through thc conucctor. unil inl-am at thc -allinrg substation i'or controllingr thc `saiil sclcctor anni oonncctor o\'c| thc two siilca otl a lino circuit in ht'rlttill. ln a tclcphonc hystcin. a terminal. a pair ol' trunkI conncctcll thcrcwith. a conin-ctor at thc cuil ol onc trunk. a non-numerical trunking witch at thc cnil of thc, othcr trunk. :l nonaiulncrical trunkinnr Switch for fonnccting r with Saitl tcrniinal. a sclcclior. moans in ai|l conncctor for contivillinc.r sahl #clcctor whcn thc call i` through thc sclcctor, incnm in tho Sclcctor for prcvcnting usc tbcrcol` whcn thc call is through thc conncctor. anil nictallic linc circnih` orcr which `will conncctor :Intl `aclcctor arc controllcil.

22T. in a tclcphonc svstcni. a Switch. an othcr switch. mcans in tbc iir t mitch for controlliu; thc acconti v witch wlicn thc call runatV pa` through thc scconil witch, n|can 4 for prcrcntiug uw ol' thc `acconil switch whcn thc call must pas through thc lirst switch. nicanl'oc prcvcnting usc of thc first switch whcn thc call lo through thc :scconil switch. and nictallic linc circuiti orcr which srrbl vswitchca arc conlrollcil to cxtcnil calla.

LH. In a tclcphonc s'wtcln. a linc circuit. a conoci-tor. a sclcrtor. lin-ans in lhc coniicctor lor controllingr tho clcclor ovor thc two aitlca` of a linc circuit in ncrics. lucana lor prcrcnting opcration ol tbc conncctor when the selector is operated to extend a call. moans for automatically restoring thc Sclcctor to normal whcn the call is through thc conncctor. and means for controlling thc connector ih accordance with the last two rligits of thc calloil number.

52S). In a telephone system, a connector, a sclcctor having' a plurality ot' levels and hav ing mcans for automatically releasing when raiscil to a particular lcvcl, moana for rcntici-ing the -onncctor opcratiivc when the siclc-ctor is thun rcleascil, mcans for prcvcnt ing operation ot' tho conncctor whcn the Sc lcctor raisctl to any other lorcl, and Inctaliicl linc circuits for controlling said connector and selector.

30. A tclcphono exchange systcm comprising a combination progrcssivcly inovablc, conncctor rcpcatnr for conncctiug a calling nml a callctl linc in a talking circuit. saiil rcpcatcr controllcd over two siilcs ot' thc talking circuit in scrios. 4 31. A tclcphonc cxcliangc s ratcm compris- 1n,f lr a combination conncctor and rcpcat'cr, a talking;r circuit from which thc aaiil combinav tion instrulncnt is cxcluilcll whcn usci! as a. rcpcatcr. a tali-Ting' circuit in which thc saiil instruincnt, is inchulcd whe-n uscil as a conncctor. and mritching nicans in saiil l'irstnxcntioncil circuit controllcil by thc 4 aiil in- .@struuicutr whcn uscil as a rcpcatcr, saiil inV Stiuincnt boing controllablo ovcr the two siclcs ot' a .portion ot' tho talking: circuit in Scrics.

32. ln a tclcphonc crichang'c HVatcni. a liuc circuit. calling mcchaniain for transniittin;r impulsos ovcr two :-iilc.sl of saiil circuit in Scric for scueling' calls, ainl a combination conncctor anrl rcpcatcr controllctl by saiil impulscs having: provisionafor prcvcnting.r opi-ration thcrcol as a conncctor for any call in which it is opcrativc as a rcpcatcr.

ln a lclcphonc Systran. a trunk tcrniinal, incinta` inclurlingl a linc circuit for con ncl-ting with aiil tcrininal` and a plurality ot' automatic stop-b v-stcp mvitchca allotlcil to anil trunk-conncctcil with Haiti tcrnlinal. whcrchy saiil tcrniiual is common to all of saiil switchcs. cach Switch controllahlc o\'cr thc two `i lcA of aaiil linc circuit' in .st-rica.

B4. [n a tclcphonc syhtcin. linc cirruita. conncctor. a plurality of sclcctors, anothcr conncctor. aml a rclay for thc first conncctor, laiil sclcitors anfl Hcconrl connector boing Succcwivclr controllalihby Haiti rclay ovcr two sichm of any of saiil iinc circuito` in scrics.

:55. ln a tclcphonc s vstcni. a talking circuit. a. pluralil ol' conncctorsconncctcil with rahl circuit. a plurality ol' aclcctors conncctcil with thc circuit hctwccn saiil conncclors. aus] circuita l'or controllinlglr sahl connccliors :mil sclcclors including; thc two niilcA ol' saiil talking." circuit in scrics.

liti, ln a lclcphonc syatcin. lncamA for l'orlnlng a talking circuit, a pluralit) ol'connutrir menus for npurzuliugr ,will morini-ritira, :unl nimm im' tiunpnrurily mindering tlm sume iii )'u ,1':1ti\' h v thvy lurinutim: sii uuid ifircuili, 'ciu'h riunire-tm' living' opvrutirfin uffrnreluiirr. with Two lliggitx nl' :i rullml umulwl', unit @zich conne/tur rnntl'nlluhlv m'rr thx` twin ships nl" u liuc circuit; in sieri 57. In n trlephmw Qystmn, i1 cmnmnu lulttery from willi-h rum-mit i.h'uppliwl flu-talking purposes und fur upvrntiug the y thin,

u lrllnl( for loe'ul milla. u truuk for cull` through unollhrr vxrluing'e nr stutinu, u am nf mnt-flits svi'ving :is u tvrininul tur heath trunks :it uur rml llurrnl'. un :nitnnautf switch for rnuneriing with mid lvrniinzil tu rxlviul a cull nvm vtlzrr truuk. uutiuuutii' humus fur rnmplrtiny mills ifi-Oni unie trunk, :mil inviami-1 fur umidi-ting rulli, l'l'mn thv fiitlwr trunk.

lf. ln a tulrphnnr h vstrni. u cunnnnn lriivry frnni whirh uri'rnt is upplieil tur i/uiliing' nui-jumps :usal t'ew npil'uiugf the' nystruaju plurality ut' trunk. :e :iinglv icrlniunl ulluiliug iii-rvs tu :lll nl' .will trunks, wlnfrulsy thv trunks uri rmy wiwi iu multiplie tn siiii tv'zuiuul, :nul :in uurunuitir. switrh ullntul t4: thvy utlu-i rml nt @urli truuli for tvuiiing rfiunmrliun lhervrnln, vurh trunk rmnprising :i [mir nl vnire-rurrunt minlnvY tors.'

il?. In :i tvlupluuw syslrrn. u rnnnnuu linitm'y frmn whirl] mirri-nt is silnpliwl for lull;A ing' gulriinw: unil t'nr nguiziling the' uwlrin, u plurnlil;V `:f trunks, :fl rrnlinul vnuuimil to :lil nl' nul trunks. ilu-um hn' rng'uging: Suhl lirniisiil le) minimi :l vulling' liniwith suiil trunk uml uaruml vnnlfrnllzxlrll5 from iluvulling; uw-ztutiun fnl' i-li-f'tinp whif'll truuk is to liiuuml in rnuaiilrting tlw ruil.

4L ln u lviviiuuw s vslrna. millingIr rncrhu nisnl fm transmitting iinimlsrr-l tnx' sriuling mills:` u ronnnun Multi-rv l'rflun which 'lll'z'vut is suppliml 'l'ni'tnll\'i|1; f furpiiwe :nul l'nl 0|- visiting thv sly-simu, :i fluir nl lruulcu, :L siuglv terulinui for Quill trunks;E when-hy lmili trunks huifl imm thisinner trrulinuh :i "HH nerim' ut, tln mul m uw trunk rvspnnsiviln Said impulwis` u truuliingf su'ili'h :il thv rml of thu Otlwr truuk, sulwvi'ilwii' hun; lri'u|i Dating ut said mnuvs'lor, lrunli luw lvmling from Suid rlluliiug Huilvi. :i first wlw-tur t'nr vm'll truukY lim` suifl reannwm iuiriug :l relay fur cuntlrnlliug thv Suhl wlwiurf: lu-n Cullurrtinu through u rlrclur is uecissury,

42. In a telephune System, u cmnnuui huttfry from which uurreut is suppliwl for tullv ing pnrpusuu unil fm' operating the system, :i mitral stuinu. u plurality of ninteutrui z-etzuious` sulnsrrilmrg Iiuos terminating ut thel `wubwntrul mations. trunk lines ':uuuecting tlm uhcvntrul stutinus with the` cunrul stutinn. ini-:zus for extending u Aall through the rrntrul stutinu Vfrom u subcvutrail stat-inn to :l culled sulu'vutrul station., uml iuwms uiioriling ili'rrc-t cnnurrtinn lwtuoril the linvs of willing' :nul culled suhsrriher of the Samir .Qnlwvnlrul Stallion.

4.2i. In az tvlophmm systfnn u comnmn hutti-ijv from which current is supplied for tlulking purpus :nul for oprrzltiug tlm system, :l miltrul stniiun, suixenlrul. htutinus, truuk huw: rnuupcting thil rrutrul station with the sulsriiutlrul stulimm. trlrphonu, iinvs lm'iuiuutA iup; :lt the sulu'cntrill stations. mum-murs nl; tim suhcvntml stations fm' uuuuurting u tele-- pluim' liiiil ut ouvl sulluvntxul siutinn with u Irlrgihono linv mi' unutlwr suluuutrul station, :nul nthvr cnnuirlurs for ifonneuiring u cullingf lim: with u rullml lilw of the suino sul i-rnlrul station.

44'. In u lvlfplimm systllin, culling uwchunisln for transmitting' impulsenV for sending rtlirr lola-il or U'unking calls, u Common hutti-ry l'rnui whirl; mirrent is supplie-l fm' teilkingr purposes uml fur operating the s wtem. u winni-vtm' for finding tim Pulli-si auluirrilu vrs linu, wlun vthvl will is lucul. prm'irlmi with u relay for rupentiugz the culling im pulses wlwn tlu ruil is to :mother station.

45. Tn :i tvlul'ihoue systvin, u fomnmn buttvrv l'ruln which current; is supplieil fm' tulking purposes unil for upolutiug the System, n mnuvrlur, mmm for c'nntiolliug suirl um inw-lm' in :wrm-lauw with the lust two digits nl' u rullml nulnlur, :nul u Svlm'tur. Suid C011- uvrlnr huving u relay for selectively runllnlliug snill urlictrix'.

ll. In u telephone system. u Commun battrry from which rurront is supplied fur talking purposvs :nul For upmutiug the :iy'stvlm u rmnurnr, nuuus fmcfmtroiling said cnnnvrtor in urrurdunt'e with tho lust two' digits n'f thirullufl number, uml n plurality of se- Ive-tors suiil rOnneOtOr having u relay for suvrossn'vly mntrollinp; said selectors.

l?. ln .-i telephone system. culling mecha-y nism for transmitting' impulses for sending wills, n rummnn lmttnrv from which current is supplimi for talking purposes and forV npvrutiug thv system, u svlvrtnr, u ('Onnvrtm'- rinspunsivv to said impulsos, nuuus for con nw'lingr 2|. willing lino with Suid counmvtnr :nul uffici-tol'` und niruus in the svlvctur fm' prm'vuting crmtiuruul uw thervnf wlwn the ruil :must pass through the rounector.

i8. In a telephone system, calling mechanism for' transmit-ting impulses for sending calls, a common battery from which current is supplied for talking purposes and for operating the system, a connector responsive to said impulses, a selector, means in the connector for controlling the selector when the call must not pass through the connector, and means in the selector for preventing use thereolz when the call must, pass through the connector. u

49. ln a telephone system, calling mechanism for transmitting impulses for sending calls. a common battery from which current is supplied for talking purposes and for operating the system, a terminal, a pair of trunks connected therewith, a connector responsive to said ilnpulses at the end of one trunk, a non-numerical trunking switch at the end of the other trunk, a non-numerical trnnking switch for connecting.;r with said terminal. a selector to which said tiret-mentioned non-numerical switch is adapted to extend connection, means in said connector for controlling said selector when the call is through the selector. and means in the selector for preventing use thereof when the call through the connector.

5o. In a telephone system, calling mechanism for transmitting impulses for sending calls. a common battery from which current is supplied for talking purposes and for operating the system. a switch responsive to said impulses. another switch. means in the first switch t'or controlling the second switch when the call must pass through the second switch. means for n'eventing use of the second switch when tlie call must pass through the first switch, and means for preventing use ofv the. lirst switch when the call is through the second switch.

5l. ln a telephone system. calling mechanism for transmitting impulses for sending calls` a common battery from which current is supplied for talking purposes and for operating the system. a connector responsive to said impulses. a selector, means in the connector for controlling the selector, means 'For preventing operation of the connector when the selector is operated to extend a. call. means for automatically restoring the selecto-r to normal when the call 's through the connector', and means for controlling thc connector in accordance with the last4 two digits of the called number.

52. In a telephone.system. calling mechanism for transmitting impulses for sending calls, a. common battery from which current is supplied for talking purposes and for operating the. system. a connector responsive to said impulses. a selector having a plurality of levels and haring means for automatically releasing when raised to a |mrlicnlar level. means for rendering the connector operative whcn the selector is thus released, and means for preventing operation of the connector when the selector `is raised to anv other level. u

53. A telephone exchange sgiistcrn comprising a selector and a connector adapted to he operated in accordance with the last digit oi' a called number. means: controlled Inf4 said connector for repeating impulses to operato said selector switch. and a common liattcrv from which current is supplied for talkingr purposes and for operating the system.

5l. A tele-phone exchange system comprising a common battery trom which current is supplied for talking purposes and for operating the system. a combination connector and repeater, a talking circuit from which the said combination instrumentis excluded when used as a repeater. a talking circuit in which the said insti-mirent is included when used as a connector, and. means in said first-mentioned circuit controlled luy the said instrument when used as a repeater.

In a telephone exchange system, caliing n'iechanisln for transmitting impulses for sending calls. a combination connector and repeater responsive to said impulses having provisions for preventing operation thereof as a connector for any call in which it is operative as a repeater. and a common hattet-y from which current is supplied for talking purposes and for operating the system.

5u. ln a telephone system. a common hatlcry from which current is supplied for talking purposes and for operating the, system. a connector. a plurality of selectors. :mother connector. and a relay for the first connector. said selectors and second connector lacing slu'cessively controllable hy said relay.

57. In a telephone system. a common haltery from which current is supplied for talking purposes and tor operating the system. a talking circuit. a plurality ot' connectors connected with said circuit. and a plurality ol" selectors connected willi the circuit lictwcen said connectors.

5H. in a telephone system. culling mechanism for transmitting impulses for sending calls. a common battery from which cur-- rent is supplied 'lor talking purposes and for operating the system. means Jfor forming a talking circuit` a plurality of connectors. means for operating said connectors in accordance with said impulses, and means t'or temporarily rendering' the same inoperative liy the formation ol'V said circuit, cach connector living operative in accordance with two digits ol' a called nunila-r.

59. ln a telephone .yslcu|. calling mechanism l'orv transmitting impulses` t'or sending calls, a pair of trunks. a single terminal lor 

